A093463 a(1) = 1; for n>1, a(n) = n*a(n-1) + 1 if n is a prime else a(n) = n*a(n-1) - 1.

1, 3, 10, 39, 196, 1175, 8226, 65807, 592262, 5922619, 65148810, 781785719, 10163214348, 142285000871, 2134275013064, 34148400209023, 580522803553392, 10449410463961055, 198538798815260046, 3970775976305200919

Offset

1,2

Links

Table of n, a(n) for n=1..20.

Mathematica

a[1] = 1; a[n_] := a[n] = (p = n*a[n - 1] + 1; If[ PrimeQ[n], p, p - 2]); Table[ a[n], {n, 20}] (* Robert G. Wilson v, Apr 08 2004 *)

Crossrefs

Cf. A093464.

Sequence in context: A221973 A303004 A054912 * A302989 A276641 A099763

Adjacent sequences: A093460 A093461 A093462 * A093464 A093465 A093466

Keyword

nonn

Author

Amarnath Murthy, Apr 05 2004

Extensions

More terms from Robert G. Wilson v, Apr 08 2004

Status

approved